#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>

int main() {
	int i = 0;
	int count = 0;
	for (i = 1; i <= 100; i++) {
		int j = i;
		while (j) {
			if (j % 10 == 9)
				count++;
			j /= 10;
		}
	}
	printf("%d\n", count);

	return 0;
}